Liquid pump



Sept. 21, 1954 G. R. ERICSON LIQUID PUMP Filed Feb. 7, 1951 Ilia. 4

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INVENTOR charge nozzle I51.

Patented Sept. 21, 1954 UNITED STATES PATENT OFFICE LIQUID PUIVIP GeorgeR. Ericson, Kirkwood, Mo., assignor to Carter Carburetor Corporation,St. Louis, Mo., a corporation ofDelaware I ApplicationFebruary 7, 1951,Serial No. 209,798

this. type having. automatic yet simple and inexpensive means. foropening. the annular passage between the; piston and cylinder wallduring the intake movements of the pump and for sealingly closing thispassage during discharge movements. A further object'is to provideinapumplof this type. sealing. means for thepurpose indicated abovewhich will conform to the mostminute irregularities invthe cylinder wallso-asto form a. liquid tight seal, and. which willbe freely movablewithrespect tothe cylinder wall.

Further objects and advantages it will. appear from the specificationandaccompanying drawings, inwhich-z.

Fig. Lisa sectional view of apumpappliedto a carburetor; i

. Fighiis afragmentary-side view of l the pump, partially sectionalized,showing the piston as it appearsduring. the discharge strokeg.

Fig. Sisa. fragmentary side view ofthe pump,-

partially sectionalized showing: the appears during theintake stroke;Fig 4, is a fragmentary side. view. of a modified form; of. my pump,partially sectionalized, show.- ing the. piston.- as it appears duringthe-discharge stroke; and. e l

Fig. isafragmentary. side view. of the modification, partiallysectionalized, showing the pistonas it-appears during the intake stroke.

Referring. nowto the drawing, the-numeral [0 generally indicates areciprocating pump com-- prising a cylinder H, piston I 2, outletpassages ll, having outlet checkvelve l4, therein, and dis- In theembodiment. shown, cylinder I lisslightly flared atits upper open endand forms partot the wall structure of a carburetor, generally indicatedatl'll Carburetor l1 comprises a mixture conduit I8: flanged at itslower end or outlet for attachment to the intake manifold of an internalcombustion engine and having: an air inlet I 9' at its upper end; achoke: valve 20; therein. for regulating the admis- 6 Claims. (Cl.103178) piston as it I sion of air, stacked venturis 22, and a throttlevalve 23 for regulating the discharge therefrom. Carburetor I! is alsoprovided with a conventional constant level fuel chamber-24 in which thefuel level is controlled by float 25. Air at atmospheric pressure isadmitted to chamber 24' through air vents 26. Fuel is supplied to themixture conduit from chamber 24 by metering valve 21,. passage 28;

and. discharge nozzle 29, and by idle port 30 and associated passageways30a. Additional fuelfor acceleration is provided by pump: l 0,locatedwithinthe constantlevel fuel chamber 24; cylinder I I of pump IDisopen at its upper end, its upper edge. being somewhat below the levelof fuel in chamber 24, so as to be at all times submerged. Piston I2 isprovided with a stem 31 connected at its upper end bylink 32 with lever33 which is 'fulorumed at one end as at; in boss 35 on the fuel chambercover. A link 31 connects the free ends of lever 33 andcrank 38 mountedon the throttleshaft, so that opening and closing movements of thethrottle cause respectively downward and upward movements of piston I 2.

diameter than cylinder I It and-isformed'with an upper annular shoulder44' of just slightly less diameter than the cylinder, so thatit formswith head element a substantially solid undersized piston having a.relatively deep annular groove 45 in its peripheral surface. Pistonhead-Misin form an inverted cup andhas formed in its upper surface aplurality of equally spaced radial oustwardly sloping slots 41, thepurpose of which willbe seen below. An annulus 48, of circularcross-section; is mounted inannular groove 45. The outer diameter ofannulus 48 is slightly greater than the inner diameter of pump cylinderll, so as to be at all times in sealing engagement with the latter. Thecross-section diameter of the annulus isslightly less than the heightanddepth of groove 45 in" order to permit vertical movement of theannulus between the upper and lower edges of groove 45. This alsopermits liquid to flow from above collar 40, through the annular spacebetween the periphery of shoulder 44 and the cylinder wall, and aroundthe inner surface of annulus 48. when annulus 48 is in its lowermostposition relative to piston 12, as shown in Fig. 3. It should be notedthat, although an annulus of circular cross-section is shown in thedrawings and described above, the annulus 48 may be of square,rectangular, or other crosssection. A coil spring 49 seated in the lowerend of cylinder II normally urges piston I2 upwardly so that as throttlevalve 23 closes, piston I2 is moved upwardly in submerged cylinder II,outlet check valve I4 seats, and a partial vacuum is created in thatportion of cylinder below piston I2; due to the pressure differential onopposite sides of piston I2 and to frictional resistance between annulus48 and the cylinder wall, annulus 48 seats on the lower edge of groove45, and as the liquid above piston I2 is displaced by the piston, itflows around the periphery of shoulder 44, above andrinside of annulus48, through slots 47, around the periphery of head 4| and into theportion of pump cylinder I below piston I2. As throttle valve 23 ismoved toward open position, piston I2 is moved downwardly. Thedifference in fluid pressures on the upper and lower surfaces of annulus48, and the slight frictional resistance between annulus 48 and the wallof cylinder H causes annulus 48 to sealingly seat against shoulder 44,thus obstructing the passage of fuel past piston I2. Thus, duringdownward movement, the escape of fluid past piston I2 is prevented andpump piston I2 forces the fuel below it through passage I3, outlet checkvalve I4, and discharge nozzle I5 into mixture conduit I8.

In order that it may accommodate itself readily to irregularities in thecylinder wall, and at the same time be easily slidable therein, annulus48 is preferably made of a tough yet deformable gasoline resistantmaterial having a low coeflicient of friction such as Teflon, atetra'fluoroethylene resin made by E. I. du Pont de Nemours & Company.Teflon is deformable under pressure, but is of low resiliency, so thatwhen forced through the slightly flared open end of pump cylinder II, aTeflon annulus readily conforms to the contour of the cylinder wall, toprovide a sealing fit. Relatively free movement of the annulus withrespect to the cylinder wall is facilitated by the low frictioncoeflicient of Teflon" (.09.12 on polished steel) and by the fact thatdue to its low resiliency, Teflon once conformed to surfaceirregularities of the cylinder tends to retain its conformation betweensuccessive movements of the piston.

Annulus 48 may also be formed of gasolineresistant synthetic rubber.

A modified form of my invention is shown in Figs. 1 and 5 in which thepiston comprises shouldered collar 48 and head 58 mounted on thenarrowed lower end portion 42 of stem 3|, and secured in abuttingrelation to each other and to the shouldered portion of stem 3| by asplit ring or other securing means. The upper portion of head 58 is offrustro-conical shape sloping downwardly and outwardly so that itcooperates with collar 48 to form a substantially solid piston with anannular groove 5| in its peripheral wall. Groove 5| thus has ahorizontal upper surface, a vertical inner surface and a downwardly andoutwardly sloping lower surface 52. An annulus 48, as described above,is mounted in groove 5|. To retain annulus 48 in sealing engagement withshoulder 44 and to permit the passage of fuel between annulus 48 andlower surface 52 of groove 5|, an annular frustroconical wave spring 53,having substantially the same slope as surface 52 is interposed betweenannulus 48 and lower surface 52 of groove 5|. Frustro-conical wavesprings are particularly suitable horizontal as well as verticalcomponents so that they not only urge annulus 48 into sealing engagementwith shoulder 44, but they also urge the annulus intosealing engagementwith cylinder Wall II; even when compressed, wave spring 53 acts as aspacer between annulus 48 and sloping surface 52 to permit the flow offluid therebetween, thus eliminating the need for slots in head element58. During upward, or intake movements of the piston due to frictionalresistance between annulus 48 and cylinder wall II and to the pressuredifferential applied to the upper surface of annulus 48, spring 53 iscompressed as shown in Fig. 5. Thus, the fuel displaced by the upwardmovement of the piston is permitted to flow around the periphery ofshoulder 44 between annulus 48 and the upper and vertical wall portionof groove 5|, between the corrugated surfaces of wave spring 53 andrespectively, annulus 48 and sloping surface 52 and through the annularspace between head 58 and cylinder wall into the portion of cylinderbelow the piston. On the downward, or discharge stroke, spring 53expands, urging annulus 48 upwardly into sealing engagement withshoulder 44 and, if a resilient, flexible annulus is used, outwardlyinto more positive sealing engagement with the wall surface of cylinderII.

It is to be understood that pumps constructed according to thisdisclosure are adapted to a wide range of uses and are not limited tothe embodiment disclosed herein; consequently, the exclusive use of allmodifications of the invention as, come within the scope of theappendedclaims is contemplated.

What is claimed is: r

1. In a pump, a cylinder having aninlet end communicating with a supplyof liquid and an outlet port in its opposite end, an undersize piston insaid cylinder having an annular groove inits periphery, an imperforateannulus mounted for axial movement in said groove, said annulus being oflarger internal diameter than the external diameter of any portion ofthe inner wall at the bottom of said groove in sealing engagement withthe wall of said cylinder, fluid passage means connecting the innerportion of said groove and the space formed between the periphery ofsaid piston and said cylinder wall, said fluid passage means beingadjacent the portion of said annulus nearest the outlet end of saidcylinder, and means for imparting reciprocating motion to said piston toengage said annulus with the edge of said groove adjacent the inlet endof said cylinder to close said fluid passage on the working stroke ofsaid pump and to disengage said annulus on. reverse movement to opensaid passage.

2. In a pump, a cylinder having an inlet end communicating with a supplyof liquid and an outlet port in its opposite end, an undersize piston insaid cylinder having an annular groove in its periphery, an imperforateannulus mounted for axial movement in said groove, said annulus being oflarger internal diameter than the external diameter of any portion ofthe inner wall at the bottom of said groove in sealing engagement withthe wall of said cylinder, a plurality of radialslots in the edge ofsaid groove nearest the outlet end of said cylinder to permit theemission of liquid from said groove, and means for impartingreciprocating motion to said piston to engage said annulus with the edgeof said groove adjacent the inlet end of said cylinder to close saidfluid passage on the working stroke of said pump and to disengage saidannulus on reverse movement to open said passage.

3. In a pump, a cylinder havin an inlet end communicating with a supplyof liquid and an outlet port in its opposite end, an undersize piston insaid cylinder having an annular groove in its periphery, an imperforateannulus mounted for axial movement in said groove, said annulus being oflarger internal diameter than the external diameter of any portion ofthe inner wall at the bottom of said groove in sealing engagement withthe wall of said cylinder, a frusto-conical wave spring means on saidpiston lightly urging said annulus outwardly of said annular groove andinto sealing engagement with the edge of said groove nearest the inletend of said cylinder, fluid passage means connecting the inner portionof said groove and the space formed between the periphery of said pistonand said cylinder wall, said means connecting the inner portion andpiston periphery being adjacent the edge of said groove nearest theoutlet end of said cylinder, and means for imparting reciprocatingmotion to said piston to engage said annulus with the edge of saidgroove adjacent the inlet end of said cylinder to close said fluidpassage on the working stroke of said pump and to disengage said annuluson reverse movement to open said passage.

4. In a pump, a cylinder having an inlet end communicating with a supplyof liquid and an outlet port in its opposite end, an undersize piston insaid cylinder having an annular groove in its periphery, an annulus oftough, deformable material of low resiliency and with a low eoeflicientof friction on smooth metal surfaces being loosely mounted in saidgroove and slidable in said cylinder, said annulus being force-fittedinto said cylinder to sealingly conform to irregularities in the wallstructure thereof, a frustro-conical wave spring means on said pistonlightly urging said annulus outwardly of said annular groove and intosealing engagement with the edge of said groove nearest the inlet end ofsaid cylinder, means formed by said spring adjacent the edge of saidgroove nearest the outlet end of said cylinder for permitting thepassage of liquid from the inner portion of said groove to the peripheryof said piston, and means for imparting reciprocating motion to saidpiston to engage said annulus with the edge of said groove adjacent theinlet end of said cylinder to close said fluid passage on the workingstroke of said pump and to disengage said annulus on reverse movementtoopen said passage.

5. In a pump, a cylinder having an inlet end communicating with a supplyof liquid and an outlet port in its opposite end, an undersize piston insaid cylinder having an annular groove in its periphery, an annulusloosely mounted in said groove, said annulus being constantly in sealingengagement with the wall of said cylinder, an annular frustro-conicalradially corrugated wave spring interposed between said annulus and theedge of said groove nearest the outlet end of said cylinder to urge saidannulus outwardly of said annular groove and into sealing engagementwith the opposite edge of said groove, the spaces between thecorrugations of said spring being adapted to permit the passage ofliquid from the inner portion of said groove to the periphery of saidpiston, and means for imparting reciprocating motion to said piston toengage said annulus with the edge of said groove adjacent the inlet endof said cylinder to close said fluid passage on the working stroke ofsaid pump and to disengage said annulus on reverse movement to open saidpassage.

6. In a pump, a cylinder having an inlet end communicating with a supplyof liquid and an outlet port in its opposite end, an undersize piston insaid cylinder having an annular groove in its periphery, an annulus oftough, deformable material of low resiliency and with a low coeflicientof friction on smooth metal surfaces being loosely mounted in saidgroove and slidable in said cylinder, said annulus being force-fittedinto said cylinder to sealing'ly conform to irregularities in the wallstructure thereof, an annular frustroconical radially corrugated wavespring interposed between said annulus and the edge of said groovenearest the outlet end of said cylinder to urge said annulus outwardlyof said annular groove and into sealing engagement with the oppositeedge of said groove, the spaces between the corrugations of said springbeing adapted to permit the passage of liquid from the inner portion ofsaid groove to the periphery of said piston, and means for impartingreciprocating motion to said piston to engage said annulus with the edgeof said groove adjacent the inlet end of said cylinder to close saidfluid passage on the: working stroke of said pump and to disengage saidannulus on reverse movement toopen said passage.

References Cited in the file of this patent UNITED STATES PATENTS

